The invention relates generally to computer systems using touch screens, and in particular, to a touch screen system suitable for use by the vision-impaired.
An electronic touch screen provides an alternative to a standard typewriter-style electronic keyboard for the entry of data into a computer. With a touch screen system, the user enters data by touching virtual buttons displayed on the computer display. The touch screen eliminates the need for a separate keyboard, and the space required for the keyboard, and may offer a more intuitive interface to users unfamiliar with computer operation.
With a touch screen system, the type, size, and number of the virtual buttons may be readily changed by changing computer""s program without changes in the associated hardware. Thus, the touch screen system offers a user-interface that may be flexibly tailored to a particular application. The ability to divide virtual buttons among different screens and to display only those screens needed by the user""s particular task can simplify data entry. The combination of text and graphical elements on the screen along with the virtual buttons can help to further guide the user through the steps of data input.
Normally, a touch screen system uses a touch screen panel which is placed directly over the viewing area of a standard computer display, for example, a CRT or a liquid crystal display (xe2x80x9cLCDxe2x80x9d). The touch screen panel provides a signal to a computer associated with the computer display indicating where on the surface of the display a stylus or finger is placed. This signal may be generated, for example, by acoustic systems detecting absorption of sound by a finger on the surface of the display or by systems using crossed beams of infrared light arrayed along x and y axes which are broken by the finger, or by laminated transparent electrodes which are physically compressed against each other to provide a point electrical contact that may be interpreted as an x and y coordinate.
Despite the advantages of touch screen systems in certain applications, they present an insurmountable barrier to the vision-impaired user who perceives only the featureless surface of the display screen knowing that it may contain one or more virtual buttons of arbitrary placement and function.
In contrast, a typewriter-style electronic keyboard, with its tactilely distinguishable keys and standard layout, can be used by both full-sighted and vision-impaired individuals.
It would be desirable to find a method of making touch screen systems accessible to both full-sighted and vision-impaired individuals, that preserves some of the advantageous aspects of a touch screen system in simplifying data entry tasks and in providing a flexible user interface. It would also be desirable to make such systems usable by those who can see but who cannot effectively read the text which is displayed and which is necessary for system use.
The present invention provides a touch screen usable by both full-sighted and vision-impaired individuals. In the invention, the spatial extent and location of the touch screen""s buttons are indicated by a distinctive sound (xe2x80x9caudio ridgexe2x80x9d) triggered when a user""s finger crosses into or out of the button boundaries separate from a spoken message which identifies the function of the button. A background sound identifies points on the screen which are outside any virtual button.
The possibility of confusing, multiple audio ridge signals, such as might be created by a touch position neither clearly in nor out of the virtual button, are eliminated by defining separate button boundaries for entry and exit of the button with the exit boundaries being somewhat larger. Intelligibility of the spoken message identifying the function of the virtual button is ensured by providing two modes of operation upon leaving a virtual button. If upon leaving the button the screen is still contacted, the spoken message is truncated facilitating the ability to move between buttons without the need to fully play each button""s spoken message. If the touch point is removed, i.e., the finger is lifted from the screen, the message continues to play to alert the user of any new button that may have been entered even instantaneously before lifting the finger.
The arbitrary spatial arrangement of the buttons may be compressed into a linear format termed a xe2x80x9cspeed listxe2x80x9d that works in conjunction with the normal virtual buttons of the touch screen but enables the user to move quickly between the various buttons. The speed list may be aligned with a guide ridge at the edge of the screen, the guide ridge including tactile separators to further aid the user in moving between these buttons.
Specifically, the touch screen of the present invention provides an electronic display screen having a display area positioned beneath a touch panel commensurate with the display area and providing a coordinate output indicating a touch point in the display area. The electronic display screen, the touch panel and audio circuitry are connected to an electronic computer which executes a stored program to identify a boundary of a virtual button with respect to the display screen and when the touch point crosses the boundary, to instruct the audio circuitry to generate an audio ridge signal delineating the boundary. The electronic computer then instructs the audio circuitry to generate a spoken message identifying the virtual button while the touch point is within the boundary.
A first audio ridge signal may be generated when the touch point crosses into the boundary of the virtual button and a second audio ridge signal may be generated when the touch point crosses out of the boundary. Further, the audio circuitry may generate a background sound while the touch point is outside the boundary.
Thus, it is one object of the invention to allow the user to scan the touch point across the screen and, through the use of audio ridge signals combined with a spoken message, obtain a mental map of button placement, size and function. The use of an audio ridge signal that is distinct from the spoken message separates the concepts of the button space and button function, improving the user""s understanding of the screen.
The electronic computer may identify a first inner boundary and a second outer boundary of the virtual button, and the audio circuitry may be instructed to generate the audio ridge signal only when the touch point is crossing into the inner boundary or when the touch point is crossing out of the outer boundary.
Thus, it is another object of the invention to provide the benefits of a separate audio ridge signal without the risk of generating ambiguous tones if the boundary is only partially crossed. By moving the boundary point, depending on the direction of entry or exit from the virtual button, multiple accidental crossings of the boundary are eliminated, aiding in intelligibility.
The electronic computer may display plurality of first virtual buttons having arbitrary locations on the display screen and may activate one of the virtual buttons to execute an associated software routine when the touch point is at the location of the activated virtual button. The computer may also generate a plurality of second virtual buttons having a one-to-one correspondence with the first plurality virtual buttons, but arranged on the display screen in the linear array. When the touch point is within the location of one of the second virtual buttons, a subroutine associated with the one virtual button and with one of the first virtual buttons is activated.
The electronic screen may further include a frame extending around the display surface and providing a ridge along which a finger may be drawn and the plurality of second virtual buttons may be arranged on the display screen adjacent and parallel to the ridge. The ridge may also include a plurality of embossments, and the virtual buttons may be arranged on the display screen to align with one each of the plurality of embossments.
Thus, it is another object of the invention to provide a duplicate set of virtual buttons on the screen arrayed in a fashion to facilitate use by a vision-impaired individual. This second list, besides being in a straight line, may have standard spacing and a limited extent. Thus the user, by running his or her finger or stylus along this line, can determine all the possible buttons on that screen.
The electronic computer may generate a spoken message identifying a virtual button when the touch point crosses into the virtual button. When the touch point then crosses out of the virtual button the message may be truncated. However, if the touch point disappears off the screen the message will be completed.
Thus, it is yet another object of the invention to ensure that a complete message is communicated to the user when the user""s finger is lifted from the touch screen, for example, prior to confirmation of button selection, and yet to allow the user to move quickly from message to message without the need to listen to the complete message. It will be understood that this feature, as well as others to be described, will be of benefit not only to the vision-impaired but also to those who have trouble reading the text messages for any reason including unfamiliarity with the written language.
The foregoing and other objects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof and in which there is shown by way of illustration, a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention, however, and reference must be made therefore to the claims herein for interpreting the scope of the invention.